|Mission type||Venus orbiter|
|Mission duration||4.5 years (planned)|
|Launch mass||2607 kg|
|Dry mass||1277 kg|
|Payload mass||255 kg|
|Start of mission|
|Launch date||2031 (planned) |
|Launch site||Centre Spatial Guyanais, Kourou|
|Orbital insertion||2034 |
|Peri altitude||220 km|
|Apo altitude||470 km|
EnVision is an orbital mission to Venus being developed by the European Space Agency (ESA) that is planned to perform high-resolution radar mapping and atmospheric studies. EnVision is designed to help scientists understand the relationships between its geological activity and the atmosphere, and it would investigate why Venus and Earth took such different evolutionary paths. The probe was selected as the fifth medium mission (M5) of ESA's Cosmic Vision programme in June 2021, with launch planned for 2031. The mission will be conducted in collaboration with NASA, with the potential sharing of responsibilities currently under assessment.
Core science measurements are: high-resolution mapping of specific targets, surface change, geomorphology, topography, subsurface, thermal emission, SO
2O, D/H ratio, gravity, spin rate, and spin axis. The specific mission's goals are:
The Lead Scientist is Richard Ghail, Royal Holloway, University of London. The two deputy lead scientists are Colin Wilson, Department of Physics, University of Oxford, UK (Science investigation lead) and Thomas Widemann, Observatoire de Paris/LESIA, France (Programme management lead).
Any orbiting spacecraft is sensitive to the local gravity field, plus the gravity field of the Sun and, to a minor extent, other planets. These gravitational perturbations generate spacecraft orbital velocity perturbations, from which the gravity field of a planet can be determined. EnVision's low-eccentricity, near-polar and relatively low altitude orbit offers the opportunity to obtain a high-resolution gravity field at each longitude and latitude of the Venusian globe. The analysis of the gravity field together with the topography gives insights on the lithospheric and crustal structure, allowing to better understand Venus's geological evolution. In the absence of seismic data, the measurements of the tidal deformation and proper motion of the planet provide the way to probe its deep internal structure (size and state of the core). The tidal deformation can be measured in the EnVision orbital velocity perturbations through the gravitational potential variations it generates (k2 tidal Love number).
The co-Principal Investigators of EnVision Radio Science and Gravity experiment are Caroline Dumoulin, LPG, Université de Nantes, France, and Pascal Rosenblatt, LPG, Université de Nantes, France.